The invention concerns processes for refining or otherwise treating oil sand ore, for example oil sand, tar sand, and oil shale, involving admixture of the ore with water to fluidize it during processing.
An oil sand deposit or ore principally contains bitumen, which is a very viscous variety of oil, combined with sand, clay, and water. In oil sand deposits, the bitumen encapsulates sand grains and captures a thin film of water between the grains and the bitumen. This water, known as connate water, is approximately 5% by weight of the ore and represents typical minimum inter granular water content. Additional water exists in the inter granular pore spaces of the ore, and may vary up to 20% by mass of the ore.
The oil sand ore can be processed by mining it from a deposit, combining the ore with water to form a slurry, and hydrotransporting the slurry to equipment for concentrating the bitumen and separating the bitumen from the tailings. “Hydrotransport” is defined as conveying solid/liquid mixtures such as slurries into or through process equipment. The bitumen is then further processed, for example by cracking and distilling, to produce petroleum products.
One known process for concentrating the bitumen, originally developed as the well-known Clarke process, is a froth flotation process in which the slurry is treated with lye (sodium hydroxide), and heated which causes the bitumen to separate from the sand grains and float to the top. The froth generated in the process is bitumen-rich and buoyant, and is removed from the top of the slurry, while the tailings (such as sand) sink to the bottom of the slurry and are removed. The slurry is heated to facilitate the froth flotation process.
Previously, a constant water flow has been added to a constant ore stream in preparation for hydrotransport.